This investigation concerns itself with the biochemical mechanisms that control corneal hydration (deturgescene). With the discovery of a relatively high amount of oxidized glutathione in the corneal endothelia of cattle and rabbits, the influence of bicarbonate, glucose, glutathione and adenosine on both total and oxidized glutathione is being investigated via perfusion. All of these compounds have been thought to have some influence on corneal hydration. Preliminary work indicates that corneal endothelial cells grown in culture may also have considerable levels of the oxidized form of glutathione. The relevance of these unusual oxidized/reduced levels of glutathione to pentose shunt enzymes in the cornea will be investigated.